A network system for transmitting vehicle data has a bidirectional multidrop ring in which data communication between data transmitting nodes and corresponding data receiving nodes is carried out even if a breakage or some other trouble occurs at a portion of the multidrop ring. This system ensures safe and reliable control of various vehicle loads for a long period of time. At least one multidrop bus or at least one further bidirectional multidrop ring may be electrically connected to the first-mentioned bidirectional multidrop ring, thereby widening the applicability of the system to the control of vehicle loads.

Two-way time division multiplex (TDM) links interlace a plurality of digital exchanges such that the possibility of path selection is available for transferring information between two of the exchanges. Instead of conventionally selecting a path for each ordered call set up, the exchanges coact such that there is generally established a one-way TDM loop between all exchanges, this loop being established by parts of said links. For calls between arbitrary exchanges the loop only is used. The operational ability of the links is monitored continuously before and after establishment of the loop. It is possible to reconfigurate the loop during calls in progress for achieving improved information transfer quality.

The invention is a multiple interconnected network of intelligent message-repeating remote nodes which employs an antibody recognition message termination process performed by all remote nodes and a remote node polling process performed by other nodes which are master units controlling remote nodes in respective zones of the network assigned to respective master nodes. Each remote node repeats only those messages originated in the local zone, to provide isolation among the master nodes.